#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)
#define FOR(i,b,e) for (int i=(int)(b); i<(int)(e); i++)
#define ALL(x) (x).begin(), (x).end()

const double PI = acos(-1);
const int MOD = 1e9 + 7;

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  int n;
  cin >> n;

  vector<int> a(n);

  int x = 0;
  REP (i, n) {
    cin >> a[i];
    x = max(x, a[i]);
  }

  if (x > 3) {
    cout << MOD << endl;
  } else {
    long long ret = 1;
    for (int i = 0; i < n; i++) {
      int cnt = a[i] == 2 ? 2 : 6;
      for (int j = 0; j < cnt; j++)
        ret *= a[i];
      ret = min<long long>(ret, 2 * MOD);
    }
    if (ret > MOD)
      cout << MOD << endl;
    else if (ret == 1)
      cout << -1 << endl;
    else
      cout << MOD % ret << endl;
  }
  
  return 0;
}